auto versus 6 speed

[hasselbach]

Hasselbach,

I think you've earned the dubious distinction of being the most arrogant member of the TDR. All that in only 6 weeks! Congrats.

The NV-5600 is a better transmission for towing than a 48RE. That's not my opinion, its a fact. Rankram is right.



Cheers,

Dave

As above. . My horse trailer at 18k or the 48 foot featherlight trailer with 2 cars that tips the scales over 20K is a tad more than the bulbous camper that you have in your pics. I've had all, a 5 speed, a 6 speed and now the auto. . Auto works better hands down.



Geez, this site is no different than the others, lots of people so set in their ways and opinions because everyone is an expert is amazing. Sorry if the facts of physics bother you. Go to school, learn, test, then come back and post something meaningful. I have cut open more converters, played with more stators, spent more time on dynos (chassis and engine), had more physics background than most of you, but guys like Pelletier call me arrogant? Get real. Get your hands dirty, Get educated, do testing, and test some more, and then come back with something substantial before attacking me...



On edit, here's some interesting tidbits of information that I researched tonight:

1. Monster trucks which weigh more than your trucks and 5th wheel homes with slide outs all have automatic transmissions. They accelerate to over 100 mph in a very short distance, all powered with blown alcohol motors. Lots of weight, lots of acceleration.

2. Caterpillar, Yamaha Heavy Industries, and other companies that make the

SUPER dump trucks for open pit mine usage (and weigh over 200,000 lbs, with a payload of over 2000,000 lbs use 'automatic transmissions). Don't believe me? Do a search, go to Caterpillar heavy equipment, etc. . what do you find? Ah for the cat its a 12 speed computer controlled automatic, the Yammer has a 10 speed automatic with a TC... .

3. Peterbuilt, Volvo, GM. I spent a few minutes checking out their web sites for semi trucks. Ah, what's this, Volvo is offering a automatic transmission for their semi trucks. Volvo claims smoother load engagement, easier on parts, more reliable and better mileage? Go to Volvo trucks and check it out. . Ford (owns Volvo) has the similar thing. GMAC in their 4500, 5500 and up trucks all have Allison transmissions as standard equipment.

4. Most Baja trucks in unlimited classes are now turning to automatics. Faster, more reliable due to less parts breakage to the driveline, etc. .

5. NHRA magazine, March issue of this year had an article of some top alcohol cars experimenting with automatics and 1 speeds (which I talked about earlier today). Problem is they are limited to tire size, and the auto's completely blew the tires away. Clutch cars didn't have this problem.

6. Top sled pullers, all automatics. I did a search on sled pulling, and every truck that was a contender had either a DDT, ATS or Suncoast transmission.



Somebody tonight made some comment that the world stopped turning when he let out his clutch. . duh. But so what? So you move your load 10 feet, then you have to push in the clutch, get another gear, let out the clutch. . and what is your load doing between gears? Probably slowing down. Then you dump the clutch again, the truck rocks over and you think you're going somewhere. . Guess what, your not, it may feel like it, but if you look over in the adjacent lane, the guy with the automatic is now way in front of you... His converter has been adjusting to the load and applying a smooth torque load to move his load while you are twisting side to side.



I could go on, but then I would be called arrogant. Seems to me that those of you who have 5 or 6 speeds are either upset that technology is changing, or just plain not with the times. Face it, rowing though the gears is as efficient as third class mail delivery. yeah, it will get there, but time is not an issue.

 

[PatrickCampbell]

As above. . My horse trailer at 18k or the 48 foot featherlight trailer with 2 cars that tips the scales over 20K is a tad more than the bulbous camper that you have in your pics. I've had all, a 5 speed, a 6 speed and now the auto. . Auto works better hands down.



Geez, this site is no different than the others, lots of people so set in their ways and opinions because everyone is an expert is amazing. Sorry if the facts of physics bother you. Go to school, learn, test, then come back and post something meaningful. I have cut open more converters, played with more stators, spent more time on dynos (chassis and engine), had more physics background than most of you, but guys like Pelletier call me arrogant? Get real. Get your hands dirty, Get educated, do testing, and test some more, and then come back with something substantial before attacking me...

Hasselbach, it seems like you love to brag about your experience so I'll start by stating I spent the past 95K miles in 9 months grossing 20,000 all over this great country with a 48RE truck. The 25K before that were with my 6spd so in the past 1 year, I've run 120K miles... thats about as much as a Class 8 OTR truck. For my current truck, I'm very psyched to get my 100K TDR front plate soon!



The auto is convenient and costs less in the beginning than the 6spd, that is about as much as I will give it.



The auto gives great torque multiplication but with it creates IMMENSE amounts of heat and is pretty much a disaster in stop and go traffic or whenever you accelerate and the TC is not locked. It'll go up to 195 F very quickly at 20K GCW. And at 195 F the life of the transmission is probably in the 4 digits.



I have 3. 73 gears and ... yes of course 4. 10s would help out with that a bit. Hindsight...



With the 6 speed you have more gears to chose from and you can put it in that gear exactly WHEN you want. If you're not an idiot who rides out the clutch, it'll last for many many miles, and even when you kill a clutch, the cost is pretty minimal if you DIY.



Sure the auto has the ability to drive with the TC locked AND unlocked, but you don't have control over when it locks and driving around unlocked AGAIN creates excessive amounts of heat.



I don't know how you can debate that...

 

[PatrickCampbell]

I could go on, but then I would be called arrogant. Seems to me that those of you who have 5 or 6 speeds are either upset that technology is changing, or just plain not with the times. Face it, rowing though the gears is as efficient as third class mail delivery. yeah, it will get there, but time is not an issue.

These are all nice points... but I thought we were discussing the auto on a Dodge truck vs. the 6spd on a Dodge truck.



Is acceleration time an issue when you're towing 20,000#? It usually takes me a good minute to get up to speed... then I'm going 75 MPH for hours on end.



In terms of efficiency, I'd go to say the 6er will yield 1-2 MPG more at any given speed.



If you are someone who drives EMPTY all or most of the time, the auto may be fine.

 

[Hohn]

Miscommunication

Hasselbach:



I welcome your input to this forum. I can understand your frustration at people not grasping certain concepts you feel are fundamental.



I'd have to say that I agree with most of what you are saying. Your comments about the torque multiplication in automatic transmissions are 100% correct.



There is a disconnect, though. While the majority of your theories are correct (I'll pick on that soon), the debate here was not centered around the THEORY of 6-speed vs auto trans, but rather the APPLICATION of the actual NV5600 vs the 48RE.



Your cited examples of auto trannies supplanting manual transmissions need to be placed in context. In the cases of heavy earthmoving equipment, the loss of absolute efficiency is less significant than the increased productivity available by increasing the speed and maneuverability of heavy equipment. In these cases, an auto trans may actually INCREASE fuel economy by reducing the cycling of the engine from low to high rpm. These engines tend to have very narrow efficiency ranges in terms of RPM band and BSFC.



Torque converters are almost a "black art" in drag racing. It's similar to the clutch technology used in various Fuel classes where trap speeds exceed 300mph. 7000HP is useless if you can't convert that tremendous energy into forward motion.



So let's talk about that process. In a drag racing car (or truck), an automatic transmission is clearly superior. This is because it can be tuned to deliver torque to the wheels in a way that matches the available traction. A drag car launches with a great deal of traction (from weight transfer and the wrinkling of the slicks), then the available traction tapers off as the weight transfers back to normal and as the slicks get taller (and thinner). Then, available traction increases rapidly as the wing starts to generate SIGNIFICANT downforce. This is why you most often see a drag car lose traction just past the 60' lights-- that the point where traction is least because the weight has transferred back to noraml but the aero aids haven't kicked in. So you need to setup your car so that it delivers the torque to the wheels in a way that matches the constantly-changing coefficient of friction of the tires on the pavement.



In this case, the ability to "tune" the nature of torque delivery in the clutch system is KEY to turning a fast time. Why? Because it's MUCH more precise to modulate the torque delivery of the transmission than it is to modulate a 7000HP nitro-burning monster. Those types of engines are more like a bomb detonation in slow motion-- they're either on or off, with the in-between being hard/impossible to modulate. Watch a driver struggle to "pedal" the car across the line sometime.



Now let's look at road racing. NASCAR guys often smoke the tires coming out of the pits. Would they prefer to do this? NO! First, it wastes the tires. Second, it's slower. But the jericho transmission uses a basic racing clutch. It, too, is hard to modulate. Because stalling the engine in the pits can be VERY costly, most teams are content to "play it safe" by smoking the tires a little bit (and it helps get them up to temp, too).

But in a PERFECT NASCAR world, the car would be able to modulate the power delivery such that the tires didn't smoke (and waste HP and fuel), but they also didn't have to run the risk of killing the engine. An auto trans would better allow this. Same goes for F1 and other road racing classes.

The same ALSO goes for motorcycle racing, where traction is even more critical. How is it that the Ducati Twins are able to win MotoGP race one after the other, while they are down on power compared to the 4-cylinders from the Japanese? Because they deliver power more smoothly (i. e. , it's easier to modulate), the rider can more easily modulate the engine to match the available traction. This is a HUGE advantage when it comes to how early the rider can apply throttle exiting a turn. You have to be able to do it when the bike's still leaned, and the contact patch is smaller. But I digress.



The point here, from a theoretical perspective, is that in many classes of racing, a refined automatic transmission would be faster. This is because in modern racing, TRACTION IS THE LIMITING COMPONENT. THUS, THE QUALITY OF THE POWER DELIVERY IS AT LEAST AS IMPORTANT AS THE AMOUNT-- at least in today's high-performance competitions.



So this is one category where an automatic transmission would or could be advantageous. I mentioned before that in heavy equipment, it could also be another advantage-- it allows for power to be applied gradually, which helps stability. it also eliminates shifting what would typically be a 10-18 or even 24-speed transmission.



Why is shifting an 18 speed inefficient? First, with that many gears, it means there's a LOT of weight added to the parts that spin. This doesn't so much hurt absolute tq delivery, but it adds friction and increases the flywheel effect. The constant shifting also wastes time--and productivity at the mine or jobsite. We've heard big trucks take off, and it seems that they sometimes only stay in a given gear for a second or two, then burn another second or two grabbing the next gear. That wastes time-- if you could be CONSTANTLY applying torque to the load, you'd get moving in a lot less time.



But now we need to address the unique circumstances of driving a CTD Dodge pickup... .



1) When we race our truck, it will be much faster with an auto. It shifts faster, and has MANY more ratios available because of the TC. It also multiplies torque, allowing a harder launch while also being easier to modulate the tq delivered to the wheels.



2) When off-roading the truck, the automatic will be superior in some key ways. The first is that we can crawl the truck at low speeds because of the slippage in the converter. It's much more precise when performing delicate maneuvers. A perfect case would be trying to get unstuck. A manual trans is MUCH more difficult to modulate-- you're either going to spin the tire or kill the engine. We don't want to spin, because that just digs in deeper, right?



3) When TOWING with our truck, we want to be able to modulate power delivery when backing. We also want to be able to have torque multiplication to get that load moving.



But this is where the problems start to come in. This is where the "theory" of the superior auto transmission falls apart to the reality of the flawed execution of the auto trans.



First, that torque multiplication comes with a price. INEFFICIENCY. In order to have torque multiplication, we MUST sacrifice efficiency. This is where the TC heat comes from.



We can best visualize this inefficiency by thinking in terms of Horsepower (power), not torque. Since we know that HP is just a function of TQ and RPM, we can do some basic math for the input to the Torque converter in fluid coupling mode. Let's assume the engine delivers this:



200hp input @ 1500rpm= 700lb ft



Assuming we are getting 2:1 torque multiplication from the TC, we might measure the following at the OUTPUT of the TC in fluid coupling:



1400lb ft @ shaft speed of 600rpm.



There's only one problem. When we multiply (1400*600)/5252 we find we only have 160HP!! We lost 40hp somewhere! We know where, too-- the TC!



As all of us who have had basic thermodynamics know, we have to account for ALL energy into and out of a frame of reference. The heat that the TC produced is mechanical energy that was converted to thermal energy! Since we have less mechanical energy out than we put in-- VOILA, INEFFICIENCY!



In short, a TC can either multiply torque, OR it can be relatively efficient-- IT CANNOT DO BOTH AT THE SAME TIME. But it CAN switch between the two-- this is the whole point of the lockup clutch-- allowing more slippage (tq multiplication) under load, while providing efficiency when NOT loaded.



So there's no debating whether or not a TC (in fluid coupling) is more efficient than a clutch. A FLUID COUPLING IS NOT AS EFFICIENT A CONDUCTOR OF MECHANICAL ENERGY AS A MECHANICAL COUPLING. Plain and simple. But the fluid coupling offers many advanages in certain applications that make this penalty worthwhile. I've outlined many of the advantages above, and there are others that make them useful in Viscous-Limited-Slip-Differentials, viscous fan clutches, etc etc.



Before we close this novel, we have to remember something else. There's much more to fuel economy than just the efficiency of the connection from engine to transmission.



If you have an engine that has a wide RPM range where it produces efficient power (in terms of BSFC), and the BSFC doesn't vary widely across the operating range, then it doesn't benefit much from the narrower RPM range that a fluid coupling or CVT would provide.



But most engines aren't like that. Their BSFC varies considerably across the operating range of the engine- especially large engines. In these cases, you could possibly see an increase in fuel economy if the fluid coupling allows the engine to stay in it's RPM range where it has the lowest BSFC.



So, the entire fuel economy debate of manual vs. auto boils down to just one pivotal question-- Does the inefficiency of having to vary the RPM of the engine (i. e. operate at less than optimal BSFC) offset the inefficiency inherent in a fluid coupling?





Who'd have thought that they educate people outside of California?

 

[PatrickCampbell]

Hohn, all that ejamacation must come from listening to NPR. Nice post.

 

[Hohn]

Nah, I studied under Rush Limbaugh

 

[WNowlan]

I will only add that with modern ATF's the heat is becoming less of a an issue. Most ATF products are either group II or group III base oils. The base oils can take the heat of a modern transmission. Some would call the group III a synthetic.



If you monitor your fluid by oil analysis and change when oxidation levels increase (TAN) you will have excellent service life. Our 48RE transmission calls for a ATF +4 product. This is a group II+ and group III base oil with a proprietary additive package. It will take the load of a stock truck for the service intervals.



On class 7 and 8 Trucks (the big ones) the industry has first gone to 50W (which is heavier than a 75W-90) synthetics and now on some models have transmission coolers for the manual transmissions.



So when you place a load on a fluid (pressure) you will get heat in either case. Both fluids will expirence oxidation from this heat. It is our job to manage the level of oxidation. It is your job to change the fluid to prevent adverse effects to the components.



I may be just getting old or wiser, but; I bought the auto for pulling my boat and horse trailer. The horses are not jerked around by my pushing in a clutch and changing gears. I believe the auto is best for pulling a live load. Now if they could only get me to miss all of the pot holes!

 

[KBennett]

Very well said Hohn.

 

[JStraw]

Auto or 6 sp??? apples or oranges?? regular or light beer??



What does it really matter? You bought the truck the way you wanted it. Right??? Isn't that the important thing.



inefficiency this, inefficiently that. Sounds like a school yard fight. :-{}



Quit worring about what someone else has or does and enjoy what you have.



They are BOTH good applications and each can be made better. Thats why we BOMB!!



Now play nice and go pick on the furds and chebbies :-laf

 

[EEdmondson]

Excellent post, Hohn. You said what needed to be said without insulting us college drop-outs like Einstein (Hasselbach) did. I was ready to put my Honda lawn mower engine coupled to a series of TC's in my useless 6sp CTD

 

[DPelletier]

Good post Hohn. I think you've hit all the key points.



Dave

 

[mberry]

Hohn,



I feel like I was just cramming for a mid-term. Excellent post!

 

[PatrickCampbell]

What does it really matter? You bought the truck the way you wanted it. Right??? Isn't that the important thing.

WAIT... I had a choice??? :{ :{ :{ :{

Excellent post, Hohn. You said what needed to be said without insulting us college drop-outs like Einstein (Hasselbach) did. I was ready to put my Honda lawn mower engine coupled to a series of TC's in my useless 6sp CTD

I thought I was the only college dropout! But you know for the 1 year I went, I was a quantum physics major. :-laf :-laf :-laf :-laf

 

[CChase]

I was ready to put my Honda lawn mower engine coupled to a series of TC's in my useless 6sp CTD

:-laf

This is where the "theory" of the superior auto transmission falls apart to the reality of the flawed execution of the auto trans.

Thank you, that's the point I and others were trying to get at. You just explained it very well.

I have a masters in mechanical engineering, and you? Tell you what, spend some time on the internet or read some books other than comics, have some foundation to speak from and then come back to the forum. I am quoting 25 years of actually performing 1000 of tests for my own racing company, and working for other firms as well. You got your basis from ????

I don't see where this comes from??? Or how it's relevant, I made a few points that were correct, and then you attack me by saying I read comic books???



Oh you have a Master's degree in mechanical engineering, well that makes you super special and I bow to your knowledge. Get over yourself. I can see that you have a further indepth knowledge of TCs than most (certainly myself), but tone yourself down a notch (i. e. personal attacks), don't sit on your self-granted high pedestal and jump in with constructive advice/information. That's why I joined this forum and others, to provide others with the knowledge I have gained over my years and pick up some more along my way.

 

[hasselbach]

:-laf







Thank you, that's the point I and others were trying to get at. You just explained it very well.







I don't see where this comes from??? Or how it's relevant, I made a few points that were correct, and then you attack me by saying I read comic books???



Oh you have a Master's degree in mechanical engineering, well that makes you super special and I bow to your knowledge. Get over yourself. I can see that you have a further indepth knowledge of TCs than most (certainly myself), but tone yourself down a notch (i. e. personal attacks), don't sit on your self-granted high pedestal and jump in with constructive advice/information. That's why I joined this forum and others, to provide others with the knowledge I have gained over my years and pick up some more along my way.

Funny post, you complain about my tone but are blind to your aggressive nature. . Pretty thin skin for someone that drives a truck.



In any event, I'm too busy right now testing a nitro motor, but Hohn's reply has some merit in some areas, but has more holes than swiss cheese in others. (but it was refreshing to read something that had foundation). I'll look over it again and respond in a more user friendly, phonetically correct, easy to understand, and pollitically correct response later. Paying $400 an hour right now on a dyno and this will have to take a back seat until later.



Relax boys, some of you need a beer and some zanex right now.



Whew, tough crowd.

 

[_MACKIN]

Hasselbach, it seems like you love to brag <snip>

That sums it up right there as you will find out.









Mac

 

[Dean Upson]

I am new to the diesel world and just bought a 04. 5 3500 6 speed. Is it okay to put it in 6th gear when im pulling a load on the highway?? I was running about 1700-1900 rpms. I don't have any extra gauges. However its only a 5,000 pound trailer.



04. 5 3500 4x4 quad cab sb stock

You are fine in 6th gear at that rpm. I have had auto, 5 spds and 6 spds and my current truck with the NV-5600 is the best of the bunch, a pleasure to drive around town or to tow with. I added the short shifter and that enhances the experience



Dean

 

[hasselbach]

That sums it up right there as you will find out.









Mac

howdy mackin! hey guys, this is the smartest person in the world when it comes to dmaxes. I have learned a ton from good old mac! he would show up at the dyno days with a little yellow fanny pack tied around his waist, you could see him for miles. .



Hey Mac, where have you been these days? Hope all is well and that super dmax is still running hard. :-laf

 

[DPelletier]

Hey Hasselbach,



So in your reply to my earlier post you stated: " ... heat is caused from not wasted engine hp, but due to fluid shearing and the transference of energy... that's like physics 101... "



BUT in your reply to BRayls' Autotrans post you state "... with this much slippage all you are doing is wasting operating efficiency. No wonder the mileage is so bad, your torque is making heat in the converter, and no (sp) moving the truck. . "



These statements directly conflict with each other and, of course, the first one is wrong. The heat in the converter ultimately comes from burning diesel fuel - basic thermodynamics... it's like Physics 101.



Ultimately you've missed the entire point of this thread. If you were to assert that the automatic transmission represents the future and that we will start to see a larger percentage of automatic transmissions, not only in automotive, but also in heavy duty applications, I would agree with you. I would also agree that automatic transmissions offer several advantages over manual transmissions, all of which have been discussed previously.

Despite this, the NV-5600 is stronger, more reliable and offers better economy than a stock 48RE. THAT is what this thread was about - discussing the NV-5600 and 48RE, not drag racing, not the future of torque converters and not even your Duramax and its Allison.



You obviously have a lot of knowledge and experience to share and should you choose to rationally debate particular points or to give some of us the benefit of some of your experience, I, for one, would welcome the comments. If you are able to do so without questioning people's, experience, education, intelligence, wisdom, religious beliefs or preferred reading materials, I think people would be much more likely to listen.



The TDR forum is unlike most others I've experienced in that there really is a friendly atmosphere, an attitude of helpfulness and (for the most part) a lack of personal attacks and name calling. I hope that if you spend more time here, you will agree.





Cheers,

Dave

 

[AKostman]

I like the auto but would like more responce at lower speeds. Is it expensive to put a lockup in? I assume this is done by a trany shop?